Radical electron-induced cellulose-semiconductors

Bio-semiconductors are expected to be similar to organic semiconductors; however, they have not been utilized in application yet. In this study, we show the origin of electron appearance, N- and S-type negative resistances, rectification, and switching effects of semiconductors with energy storage capacities of up to 418.5 mJ/m2 using granulated amorphous kenaf cellulose particles (AKCPs). The radical electrons in AKCP at 295 K appear in cellulose via the glycosidic bond C1–O1·–C4. Hall effect measurements indicate an n–type semiconductor with a carrier concentration of 9.89 × 1015/cm3, which corresponds to a mobility of 10.66 cm2/Vs and an electric resistivity of 9.80 × 102 Ωcm at 298 K. The conduction mechanism in the kenaf tissue was modelled from AC impedance curves. The light and flexible cellulose-semiconductors may open up new avenues in soft electronics such as switching effect devices and bio-sensors, primarily because they are composed of renewable natural compounds.

diagram of the cellulose nano fibre below the transparent film surface were observed using confocal scanning microscopy (OPTELICS HYBRID+, Lasertec, Japan).The depth from the surface was calculated using z-scale values at the peak intensity positions of the interference fringes generated by white light and the two-beam interference objective lens.
Attenuated Total Reflection Transmission FT-IR spectra for AKCP film with thickness of approximately 5 μm were collected at 298 K over the 4000-550 cm −1 regions, with a resolution of 4 cm −1 , using a JASCO model FT/IR 6300 spectrometer.For each sample, 100 scans were used for FT-IR.ESR measurements were performed at room temperature with a Q-band ESR spectrometer (JES-X330, JEOL) [power: 10 mW, modulation width: 2.0 mT, timer constant:0.1 s, sweep time: 60 s] at 298 and 103 K. Subsequently, g-values were measured relative to the fourth signal from the lower magnetic field (g =1.981) of Mn 2+ in MgO.Hall measurements were performed in an AC magnetic field of 2.5 Tpkpk with magnetic rotation speeds of 1 or 2 rpm for 10 V at 298 K using the conventional Van der Pauw technique with samples on an Si substrate, using a Hall effect measurement system (PDL-1000, SEMILAB).The sample structure was analysed through X-ray diffraction (XRD) in the reflection mode with monochromatic Cu Kα radiation.Selectedarea electron diffraction (SAED) measurements were performed using a transmission electron microscopy (JEM-2100; JEOL).Surface morphologies were analysed using atomic force microscope (NanoScope V/Dimension Icon, Bruker AXS).All electronic measurements were performed in an Al shield box to prevent the results from being affected by electromagnetic interference from surroundings.

S2. Mineral contents
The problem of minerals being absorbed from soil through water is an important concern for semiconductor properties.Therefore, the contents of forty elements in AKCP were determined ICP analysis.Table S1 shows the mass contents of these mineral elements.
Although the amount of minerals in AKCP is extremely small, it is currently unknown whether these amounts affect semiconductor properties or not.

S3. Effects of electron irradiation on AKCP
In electron observations of CNFs made from Varonia, Cotton, Ramie, wood, and Acetobacter cellulose, damage has been reported when the electron dose to the specimen exceeds approximately 3╳10 20 e/m 2 at an accelerated voltage of 200 kV 35 .In this study, AKCP samples were examined for electron irradiation damage by electron diffraction for 0, 600, and 1,800 s of irradiation at 100 kV with a dose rate of 1.16╳10 25 e/m 2 s .The SAED patterns are shown in Fig. S1.No degradation was observed during irradiation at 100 kV.The halo Debye rings were slightly blurred after 1,800 s of irradiation but did not decompose or disappear.

S4. Structural morphology characterised via white interferometer microscopy (WIM), transmission electron microscopy (TEM) and atomic force microscopy (AFM).
The structural morphology of the AKCP samples was investigated.Figure S2a and S2b illustrate an internal microstructure and angular spectra diagram of the distribution of grain shape orientations at 2 µm below the transparent surface of the AKCP, which were obtained using WIM.The angular spectrum is oriented in almost all directions, indicating defibrillated particles.However, internal angular spectral diagram (Fig. S2d) of the microstructure (Fig. S2c) of the AKCF, which was used as a comparison is fibrous with a clear orientation and non-defibrillated particles.The wide-field X-ray analysis pattern (Fig. S2e) comprises amorphous cellulose, and it is characterised by three broad peaks at approximately 16°, 23°, and 70°3 6 .Figure S2f shows a scanning electron microscopy (SEM) photograph at 5 keV.The surface contains particulate aggregates of approximately  can be inferred from the amorphous XRD pattern shown in Fig. S2e, the Nyquist diagram shown in Fig. 3b, and the amorphous phase in Fig. S4.Furthermore, the samples used in this study may exist as clusters composed of cellulose, as inferred from the amorphous alloys composed of dodecahedral, icosahedral [37][38][39] , C60 40 and icosahedral (H2O)280 water clusters 41 .

S5. TEM image and SAED pattern of nanofibril phases
The TEM image and SAED pattern for the outside regions of the nanofibril phase, which makes up the majority of the tissue, are illustrated in Fig. S3, depicting a completely amorphous hollow pattern.

S7. Consideration of radicals on cellulose molecule
The effect of one-sidedness, indicated by the difference in the electronegativity of the atoms in a compound owing to the ease with which the atoms attract or release electrons, is called the induced effect and is a guide to organic radical generation.In cellulose (C6H10O5) n, when comparing the electronegativity of O5 and O1, the electrons in O5 are biased towards C1, as shown in Fig. 2d, primarily because the electronegativity of O1 between the two glucose units is greater than that of O5.Thus, one glucose unit becomes an electron-withdrawing group because the electronegativities of C, H, and O are 2.55, 2.20 and 3.44, respectively, and O1 is biased towards electrons with an electronegativity of 4.26.On the other hand, electrons are biased towards O2 and O3 with an electronegativity of 2.48 and towards O6 with an electronegativity of 2.29.Therefore, most atoms are biased towards O1 in C1-O1.Consequently, an electron radical is induced in O1.Radicals formed on the alkoxyl groups of side chains, such as positions C1 and C2, are more reactive than radicals on the glucose units of the main chain, and they cannot be C-O • radicals because they quickly proceed to secondary reactions such as subsequent rearrangement and recombination.On the other hand, the radical formed at position C-6 is a secondary radical, which is unstable and therefore preferred for the rapid progress of cross-linking, but can be excluded from consideration of the radical formation mechanism.
Thus, the radical electrons are derived from the glycosidic bond, C1-O • -C4, between the

S9. Conduction mechanism
Negative-resistance devices have a differential resistance defined as R = dV/dI < 0. They can be classified into static negative resistance 44 , where the negative resistance characteristic appears on the DC I-V characteristic, and dynamic negative resistance, where the negative resistance characteristic does not appear on the DC I-V characteristic but shows negative resistance owing to effects such as carrier travel time.Static negativeresistance devices can be explained in terms of pn junction theory, such as tunnel diodes, thyristors, and junk-shot transistors.Dynamic negative-resistance devices, such as impact avalanche transit time (IMPATT) and Gunn diodes, can be explained by the carrier travel time and peculiarities of the band structure of the material.The bio-semiconductor phenomenon in this study is not caused by a pn junction but by a Schottky junction.This means that the phenomenon is induced by the electron avalanche and the carrier travelling speed.
Systems that exhibit differential negative resistance can be divided into two classes: voltage-controlled (N-type) and current-controlled (S-type) 45 .The mechanisms causing these negative resistances can be divided into three broad categories.(1) processes caused by the Joule heating of conduction electrons, which causes changes in their number or mobility, (2) processes inspired by special semi-permanent space charge distributions, and (3) processes caused by phase changes or atomic arrangements in the host insulator.
The semiconducting properties in this study are involved in the second category, as inferred from the organic-induced electrons in Fig. 2

Fig
Fig. S1 SAED patterns of AKCP irradiated at 100 kV with 1.16╳10 25 e/m 2 s for 0, 600, and Figure S2h displays a TEM image of the sample observed at 100 keV.It is a

Fig. S3
Fig. S3 TEM image and SAED pattern of the amorphous phase.
Figs. 3(b) and 3(c), and the cellulose molecular model in Fig. 4(a).Models involving this